Actuator and valve arrangement

ABSTRACT

A number of variations may include an actuator and valve arrangement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 14/488,700filed Sep. 17, 2014 which claims the benefit of U.S. ProvisionalApplication No. 61/879,523 filed Sep. 18, 2013.

FIG. 1 is a schematic illustration of a number of variations includingan engine which may have an intake manifold and an exhaust manifold.

FIG. 2 shows a variation of a typical D.C. motor actuated poppet valveassembly 100.

FIG. 3A is a side view of a housing having a valve seat disposedtherein.

FIG. 3B is a section view taken along line D-D of FIG. 3A.

FIG. 4 is an enlarged sectional view of a valve.

FIG. 5 is a perspective view of a valve without a housing.

FIG. 6 is a perspective view of a valve without a housing.

FIG. 7 shows a D.C. motor actuated poppet valve assembly.

FIG. 8A is a side view of D.C. motor actuated poppet valve assembly.

FIG. 8B is a section view taken along line B-B of FIG. 8A.

FIG. 9 illustrates a housing may have counter bore section, which mayinclude multiple stepped sections having different diameters.

FIG. 9B is a sectional view taken along line B-B of FIG. 9.

FIG. 10 illustrates a spacer that may be a generally cylindrical partand may have castellation features separated by a circumferentialrecess.

FIG. 11 illustrates a valve with portions removed.

FIG. 12 is an enlarged sectional view of a valve.

FIG. 13 illustrates a cover material over molded on the lead frame.

FIG. 14 illustrates the lead frame with cover material removed.

FIG. 15 illustrates one variation of an enlarged section of cover withposition sensor.

FIG. 1 is a schematic illustrating a number of variations including anengine (1) which may have an intake manifold (2) and an exhaust Manifold(3). The EGR system may have an exhaust gas recirculation (EGR) valve(4) that controls the flow of exhaust gas to intake manifold (2). An EGRcooler (5) may be used to reduce the temperature of the exhaust gas.Conduits (6), (7), (8), (9) and (10) provide the interconnection betweenthe exhaust manifold (3), EGR cooler (5), EGR Valve (4), and Intakemanifold (2). An electrically controlled EGR valve may be provided. Anelectronic control unit (ECU) (11) may provide a signal that willcontrol the opening/closing of the valve. As the EGR valve opens andcloses it will increase or decrease the flow rate of exhaust gas to theintake manifold. A throttle valve (12) may be provided to controlairflow into the intake manifold.

The required EGR flow rate is dependent upon several factors thatinclude the displacement of the engine and the pressure differentialbetween the exhaust and the intake system.

Referring again to FIG. 1, the ECU (11) may be programmed with a map ofengine operating conditions and a desired EGR flow for each condition.EGR valve (4) may have a position sensor that is connected to the ECU(11) and to provide an output signal that is relative to the valveposition and flow through the valve. The desired flow may be translatedto a position sensor output signal and an actuator control signal. Thecontrol signal may be applied to the actuator, of the EGR valve (4),causing the valve to move away from the valve seat and allow exhaust gasto flow from the exhaust manifold (3) to intake manifold (2). Theposition sensor and its output signal may be part of a closed loopcontrol system for the EGR valve. The position sensor may providefeedback to the ECU that will indicate if it has achieved the desiredposition and related flow. The ECU may adjust the actuator controlsignal to achieve-or-maintain the desired valve position. Therecirculated exhaust gas will mix with the incoming air and bedistributed to the engine cylinders by the intake manifold. The mixtureof exhaust gas, air, and fuel will determine combustion temperature andcontrol of the level of NOX and particulate matter.

Fuel economy may also be improved by the use an EGR system. When the EGRopens, the vacuum or pressure in the intake manifold and exhaust may bereduced. The reduction of vacuum or pressure may reduce the pumpinglosses of the engine the amount of fuel used by the engine.

A number of electric actuators such as linear solenoids, D. C. motors,torque motors, and stepper motors may be used to actuate the EGR valve.Valve position sensing may also be achieved by alternate methods suchas, but not limited to, counting steps of a stepper motor or byregulating vacuum to a pneumatically controlled EGR valve.

A number of valve types such as throttle, poppet, or flap may be used tocontrol the flow exhaust gas.

The type of actuator and valve may be determined, in part, by the typeof engine and EGR system used for emission controls or fuel economy. Forexample, the exhaust from a diesel engine may contain high amounts ofresidue that may form a sticky lacquer like substance that may provideresistance to opening the valve. A higher force actuator, in excess of300N, may be required to open the valve. D.C. motor actuators withmulti-stage drives have been used for these EGR valve applications.

In another example, the exhaust from a gasoline engine may contain alesser degree of residue due, in part, to the higher exhausttemperatures and chemical reaction during combustion. The operatingforce of the actuator may be substantially less for these engines.Linear solenoid actuators have been used for these EGR valveapplications and their typical operating forces range from 20N to 2Nbetween the open and closed valve conditions.

More recent engine developments, such as GDI engines (gasoline directinjection) have made use of “cooled EGR”. The faster cooling of exhaustgas may increase the level of exhaust residue that can resist the EGRvalve movement and increase the requirement for actuator force. Althoughthe level of residue is higher for these gasoline engines it may not beas severe as the residue from the diesel engine and the actuator forcerequirement may be less.

Several types of valves may be used for EGR applications. For example: apoppet style, flap style, or throttle style valve could be capable ofproviding these functions. These valves may be actuated by severaldifferent types of actuators, for example: vacuum/pressure motors, D.C.motor, torque motor, stepper motor, or linear solenoid type actuatorscould be capable of actuating the valve.

FIG. 2 shows a variation of a typical D.C. motor actuated poppet valveassembly 100. The valve assembly 100 may have a unitary actuator andvalve housing 101. The housing 101 may be made of aluminum, cast iron,or other suitable material. The housing may have an inlet 102 forreceiving a fluid and an outlet 103 for delivering the fluid. Referringto FIG. 3A and section view FIG. 3B, a valve seat 104 may be disposedwithin valve housing 101 and secured by staking, casting it in position,or other suitable means. A moveable poppet valve 105 may be coaxial withthe valve seat 104 for controlling the fluid flow through the valveassembly.

The poppet 105 may be fully closed and seated on the valve seat 104 andessentially block flow between the inlet 102 and outlet 103. Poppetvalve 105 may move axially away from valve seat 104 to a fully openposition where maximum flow will occur between the inlet 102 and outlet103. Poppet valve 105 may also move axially away from the valve seat 104to a number of intermediate positions between the fully closed and fullyopen positions to control the rate of fluid flow at values that are lessthan the maximum fluid flow rate.

A valve stem 106 may be located within the housing and may be coaxialwith poppet valve 105 and valve seat 104. The valve stem 106 may have afirst end 107 that may connect to a central location of poppet valve105. Poppet valve 105 may be attached to the valve stem by welding,riveting, staking or other suitable means. Valve stem 106 may be guidedand supported by a bushing assembly 108 that may be coaxial with thevalve stem 106 and disposed within housing 101. Referring to partialsection view FIG. 4, a bushing assembly 108 may have a first end 109with counter bore section 110 which may have multiple stepped sections110A, 110B, and 110C having different diameters. A first stem seal 111,stem scraper 112, and retainer washer 113 may be coaxial with the valvestem 106 and disposed within the multiple stepped sections 110A, 110B,and 110C of counter bore section 110. Stem scraper 112 may be disposedin a stepped section 110B of counter bore section 110. Stem scraper 112may have an outer diameter that is smaller than the inside diameter ofstepped section 110B and may move within stepped section 110B. Stemscraper 112 will have an inside diameter that is greater than valve stem106 but will be capable of removing unwanted debris from valve stem 106.

Retainer washer 113 may be installed stepped section 110C of counterbore section 110 and is secured to the bushing assembly by staking orother suitable means. Retainer washer 113 may secure the stem seal 111and stem scraper 112 in the bushing assembly 108.

Bushing assembly 108 may have a second end 114 with counter section 115consisting of multiple stepped sections 115A and 115B. A second stemseal 116 and retainer washer 117 may be coaxial with the valve stem 106and disposed within multiple stepped sections 115A and 115B of counterbore section 115. The retainer washer 117 may be installed in steppedsection 115A of counter bore section 115 and may be secured to thebushing assembly by staking or other suitable means. Retainer washer 117may secure the stem seal 116 in the bushing assembly 108.

The first stem seal 111 and second stem seal 116 may define a radialspace 118 between the outer diameter of valve stem 106 and the innerdiameter of bushing assembly 108. Radial space 118 may extend axiallyalong a length of the bushing assembly 108 and valve stem 106 defined bythe positions of stem seals 111 and 116. Stem seal 111 may preventdebris from entering space 118 from the first end 109 of bushingassembly 108 and stem seal 116 may prevent debris from entering space118 from the second end 114 of bushing assembly 108.

Two O-ring seals 119 and 120 may be spaced axially along the outsidediameter of bushing 108. Bushing 108 may have a circumferentialcontoured groove 121 located in the space between O-rings 119 and 120.When bushing 108 is installed in housing 101, the O-ring seals 119 and120 may create a seal between the bushing assembly 108 and the housing101. The circumferential groove 121 may define a space 122 betweenO-ring seals 119, 120, and housing 101. Contoured groove 121 may have atleast one passage 123, shown as a hidden line, which will allow fluidcommunication between space 122 and space 118. Valve housing 101 mayhave a vent passage 124 that will allow fluid communication betweenspace 122 and atmosphere. Passage 123, space 122, and vent passage 124may allow space 118 to be essentially at atmospheric conditions. Thismay limit potential contamination from being forced into actuatorportion 129 of valve assembly 100.

Referring to FIGS. 3B and 4, valve stem 106 may have a second end 125extending axially through the second end 114 of bushing assembly 108. Alink 126 may be attached to second 125 end of valve stem 106 byriveting, staking or other suitable means. A ball bearing 127 may beattached to link 126 by a pin 128 and may be secured by riveting,staking or other suitable means.

Referring to FIGS. 3B, 4, and 5, housing 101 may have an actuatorportion 129 for receiving the actuator components: D.C. motor 130,intermediate gear 134, Pin 137, output gear 139, Shaft 140, bearing 141,and spring 142. D.C. motor 130 may be installed into actuator portion129 and may be retained by threaded fasteners 131. D.C. motor 130 mayhave a shaft 132 that is rotatable when an electrical control signal isapplied to the D.C. motor. A pinion gear 133 may be attached to shaft132 and will rotate with shaft 132. Intermediate gear 134 may have afirst gear section 135 that engages and rotates with pinion gear 133.Intermediate gear 134 may also have a central through-hole 136 that maybe sized to slide over pin 137. Pin 137 may be press fit into housing101 and will allow rotation of Intermediate gear 134 about its axis.Intermediate gear 134 may have a second gear section 138 that isintegrally formed as part of the intermediated gear 134.

Output gear 139 may be attached to a shaft 140 by press fit or othersuitable means. The shaft 140 may be supported by at least one bearing141 that may be installed into housing 101 and retained by press fit orother suitable means. Bearing 141 may allow rotation of the output gear139 about the axis of shaft 140. Output gear 139 may engage the secondgear section 138 of intermediated gear 134. When an electrical controlsignal is applied to D.C. motor 130, motor shaft 132 will rotate. Piniongear 133, first and second gear sections 135, 138 of the intermediategear 134, and output gear 139 may rotate in response to the applicationof the electrical control signal and the rotation of the motor shaft132.

Output gear 139 may have a cam 143 integrally formed in the gear. Ballbearing 127, attached to link 126, is engaged with cam 143. There may besufficient clearance between the cam and outside diameter of the bearingto allow relative movement. Contacting surfaces 144 and 145 of cam 143may be eccentric with the axis of the output gear 139 therefore rotationof the output gear will cause bearing 127 to move radially with respectto the center of the output shaft 140. Since bearing 127, link 126,valve stem 106, and poppet valve 105 are interconnected; rotation of theoutput gear 139 in a first direction may cause the poppet valve to moveaway from the valve seat and rotation of the output gear 139 in a seconddirection will cause the poppet valve to towards the valve seat. Thismovement of the poppet valve 105 relative to the valve seat 104 willallow control of fluid flow through the valve between the inlet 102 andoutlet 103.

The size of: pinion gear 133, first and second gear sections 135, 138 ofthe intermediate gear 134, and output gear 139 may provide a mechanicaladvantage that will increase the torque provided by D.C. motor 130. Thesize of the gears and shape of cam 143 will determine the overallmechanical advantage and force available to open and close the valve.

A torsion spring 142 may be coaxial with output gear 139 and shaft 140.A first end of torsion spring 142 may be engaged with output gear 139and a second end may engage with housing 101. The bias of torsion spring142 may be applied in manner that will cause output gear 139 to rotatein a direction that will cause poppet valve 105 to seat against valveseat 104 essentially blocking fluid flow between inlet 102 and outlet103.

Referring to FIGS. 2, 5, and 6, in a number of variations the valveassembly 100 may have a lead frame 146 imbedded in cover 147. The cover147 may be attached to housing 101 by threaded fasteners, crimp ring, orother suitable means. A seal 154 may be located between the cover andhousing to prevent debris from entering the housing. FIG. 5 shows thelead frame with cover material removed and FIG. 6 shows cover materialover molded on the lead frame 146. According to a number of variationslead frame 146 may include several individual terminals. For example,terminals 148 and 149 may provide electrical connection to D.C. motor130 and position sensor 153. A molded electrical connector 151 may beformed in cover 147. A mating connector, with terminals, may engageelectrical connector 151 and the terminals of lead frame 146 and makethe electrical connections to ECU 152.

The valve position and fluid flow may be controlled by a closed loopcontrol system that may be part of and electrical control unit (ECU) 152shown in FIG. 2. The ECU may provide a control signal to the D.C. motor130 and receive poppet valve position feedback from position sensor 153.Each valve position may correspond to a specific position sensor outputvoltage. The ECU may adjust the control signal to the D.C. motor toachieve and maintain a specific valve position that corresponds to thespecific valve position voltage.

The position sensor 153 may be a non-contacting type and may usemagneto-resistive, inductive, Hall Effect, or other suitable technology.Sensor 153 may have a sensing circuit 150 that may receive feedback froma sensing element 152. Sensing circuit 150 may be disposed in cover 147and connected to the lead frame 146 by soldering, contact pressure, orother suitable means. The sensing element 152 may be attached to theoutput gear 139, output shaft 140, or other suitable location. Sensingelement 152 may provide feedback to the sensing circuit 150 when outputgear 139 may be rotated in response to an electrical control signalapplied to D.C. motor 130. The sensing circuit may provide a valveposition voltage that corresponds to a specific gear and valve position.

It should be noted there may be a small error in actual valve positionsince the sensor element may be located on the gear and may be measuringthe gear position. The clearance between bearing 127 and contactingsurfaces 144 and 145 of cam 143 may allow some free movement of bearing127, valve stem 106, and poppet valve 105 that may result in a smallvalve position error.

Valve assembly 100 is capable of high fluid flow and high valveoperating forces that may be suitable for some applications. The highercapability may result in a higher cost and design complexity. Someapplications may not need the higher capability or complexity. It istherefore important to “right size” an actuator and valve assembly thatwill be a better fit for these application.

FIG. 7 shows D.C. motor actuated poppet valve assembly 200. The valveassembly may have a unitary actuator and valve housing 201. The housingmay be made of aluminum, cast iron or other suitable material. Thehousing may have an inlet 202, for receiving a fluid, and an outlet 203for delivering the fluid. Referring to FIG. 8A and section view FIG. 8B,a valve seat 204 may be disposed within valve housing 201 and secured bystaking, casting it in position, or other suitable means. A moveablepoppet valve 205 may be coaxial with the valve seat for controlling thefluid flow through the valve assembly 200.

The poppet valve 205 may be fully closed and seated on the valve seat204 and essentially block flow between the inlet 202 and outlet 203. Thepoppet valve 205 may move axially away from valve seat 204 to a fullyopen position where maximum flow will occur between the inlet 202 andoutlet 203. Poppet valve 205 may also move axially away from the valveseat 204 to a number of intermediate positions between the fully closedand fully open positions to control the rate of fluid flow at valuesthat are less than the maximum fluid flow rate.

A valve stem 206 may be located within the housing and may be coaxialwith poppet valve 205 and valve seat 204. The valve stem 206 has a firstend 207 that is connect to a central location of poppet valve 205.Connection may be made by welding, riveting, staking, or other suitablemeans. Valve stem 206 may be guided and supported by a bushing 208 thatmay be coaxial with the valve stem 206 and disposed within housing 201.

Referring to partial section view FIG. 9, housing 201 may have counterbore section 210, which may include multiple stepped sections havingdifferent diameters. A stem shield-retainer 213, stem scraper 212,bushing 208, first stem seal 211, spacer 214, and second stem seal 216may be coaxial with the valve stem 206 and disposed within counter boresection 210. Counter bore section 210 may be designed to receive stemshield-retainer 213, stem scraper 212, bushing 208, first stem seal 211,spacer 214, and second stem seal 216 from one direction, for example,direction A shown in FIG. 8B.

Referring to partial section view FIG. 9, sealing system 265 includingfirst stem seal 211, a spacer 214, and second stem seal 216 may bedisposed in a first stepped section 217 of counter bore section 210. Thestem seals 211 and 216 may be spaced apart by spacer 214. Each stem sealmay provide an outer radial seal to housing 201 and inner radial seal tothe valve stem 206. Referring to FIG. 10, spacer 214 may be a generallycylindrical part and may have castellation features 221 and 222separated by a circumferential recess 223. Spacer 214 also may have aninner surface 224 that has a diameter greater than valve stem 206 toallow unrestricted movement and contact. Castellation features 221, 222,inner surface 224, and circumferential recess 223 create a space 258within housing 201. Housing 201 may have a vent passage 227, locatedbetween first stem seal 211 and second stem seal 216, that may allowfluid communication between space 258 and atmosphere. Vent passage 227may essentially keep space 258 at atmospheric conditions in the event ofsmall levels of leakage past either stem seal. This may limit potentialcontamination from being forced into either valve portion 225 oractuator portion 226 of valve assembly 200.

Referring to FIG. 8B and FIG. 9, bushing 208 may be disposed in a secondstepped section 218 of counter bore section 210. Bushing 208 may have afirst end 263 and second end 264 and it may be retained in the housingby staking, press fit, or other suitable means. Bushing 208 supports andguides valve stem 206 and may retain sealing system 265 including firststem seal 211, spacer 214, and second stem seal 216 in housing 201.First stem seal 211, spacer 214, and second stem seal 216 may be locatedat first end 263 of bushing 208. This location is further away fromfluid flow through valve assembly 200 and this may be desirable when thefluid flow has a high temperature that may exceed the operatingtemperature of the seals.

It is also possible to locate sealing system 265 in a location closer tothe fluid flow if the temperature of the fluid flow is lower and withinthe operating temperature of the seals. FIG. 9B shows sealing system 265including first stem seal 211, spacer 214, and second stem seal 216located at second end 264 of bushing 208. Referring to FIG. 9B, thenumbers shown for the components and features are similar to number usedfor components and features used in FIG. 9. Again, referring to FIG. 9B,the location of vent 227 and space 258 may be moved to a suitablelocation in the area around the second end 264 of bushing 208. Themultiple stepped features of counter bore 210 may be adjusted for thenew seal and spacer location at second end 264 of bushing 208. Counterbore section 210 may also be designed to receive stem shield-retainer213, stem scraper 212, bushing 208, first stem seal 211, spacer 214, andsecond stem seal 216, from one direction, for example, direction A shownin FIG. 9B.

FIG. 8B and FIG. 9 show anti-contamination system 266 including stemscraper 212 and stem shield-retainer 213 which may be located at secondend 264 of bushing 208. Stem scraper 212 may be disposed in a thirdstepped section 219 of counter bore section 210. Stem scraper 212 mayhave an outer diameter that is smaller than the inside diameter if thirdstepped section 219 and may move within third stepped section 219. Stemscraper may have an inside diameter that is greater than valve stem 206but may be capable of removing unwanted debris from valve stem 206. Stemshield-retainer 213 may be disposed in a fourth stepped section 220 ofcounter bore section 210. Stem shield-retainer 213 may be retained inthe housing by a press fit, staking or other suitable means. Stemshield-retainer 213 may retain stem scraper 212 in housing 206 and maylimit the depositing of debris on valve stem 206. It should be notedthat stem scraper 212 and stem shield-retainer 213 are shown as twoseparate components but it is possible to combine their functions into asingle component by selecting a suitable clearance between the outsidediameter of valve stem 206 and the corresponding inside diameter of stemshield-retainer 213.

Valve stem 206 may have a second end 259 extending axially throughsecond stem seal 216 into actuator portion 226. A link 228 may bedisposed in housing 201 and attached to the second end 259 of valve stem206 by threaded insert, riveting, staking, or other suitable means. Link228 may be made of material such as injection molded plastic, die castmetal, or other suitable materials. A bearing 229 may be attached tolink 228 by a pin 230 and may be secured by a press fit, riveting,staking or other suitable means.

Bias springs 231, 232 may be disposed within housing 201. First ends233, 234 of bias springs 231, 232 may bear against stem link 228. Secondends 235, 236 of bias springs 231, 232 may bear against housing 201. Thecompressed force 267 of bias springs 231, 232 may cause stem link 228,valve shaft 206, and poppet valve 205 to move in direction A and seatpoppet valve 205 on valve seat 204 and essentially block fluid flowbetween inlet 202 and outlet 203. It may be noted that although two biassprings were used in this illustrative variation, it is possible to useone spring. The spring or springs may also be located in anotherlocation. For example, a spring may be installed coaxially on the valveshaft 206 and bear against housing 201 and link 228. The location of thespring may be determined by the desired bias force, size of the spring,available space in the housing, or other factors.

Referring to FIGS. 8B, 11, and 12, housing 201 has an actuator portion226 for receiving the actuator components: D.C. motor 237, cam-gear 238,and pin 239. D.C. motor 237 may be installed into actuator portion 226and may be retained by threaded fasteners 240 or other suitable means.D.C. motor 237 may have a shaft 241 that is rotatable when an electricalcontrol signal is applied to the D.C. motor 237. A pinion gear 242 maybe attached to shaft 241 and will rotate with the shaft. Cam-gear 238has a gear section 243 that engages and rotates with pinion gear 242.Cam-gear 238 also has a central through-hole 244 that may be sized toslide over pin 239. Pin 239 may be press fit into housing 201 and mayallow rotation of cam-gear 238 about its axis. Referring to FIG. 12,cam-gear 238 may have a cam portion 245 integrally formed about thecentral through-hole 244. Cam portion 245 may rotate with cam gear 238.

Referring to FIGS. 8B and 12, bearing 229, attached to stem link 228,may be positioned in relation to cam portion 245. The force of biassprings 231, 232 may cause stem link 228 and bearing 229 to move indirection A towards cam portion 245 and, under some conditions, maycause bearing 229 to bear against cam portion 245. When an electricalcontrol signal is applied to D.C. motor 237, it may rotate the D.C.motor in a first direction causing shaft 241, pinion gear 242, cam-gear238, and cam portion 245 to rotate and bear against bearing 229. Thetorque and force developed by D.C. motor 237, pinion gear 242, cam-gear238, and cam portion 245 may be sufficient to overcome the compressedforce 267 of bias springs 231,232, and cause bearing 229, stem link 228,valve stem 206, and poppet valve 205 to move in direction B and unseatpoppet valve 205 from valve seat 204 and allow fluid flow between inlet202 and outlet 203. The bias springs 231, 232 may compress in height aspoppet valve 205 is displaced away from valve seat 204. The compressedforce 267 may increase as the compressed height of bias springs 231, 232decreases.

The axial displacement of poppet valve 205 from valve seat 204 may inpart be determined by the intensity level of the control signal appliedto the D.C. motor 237. A higher intensity level may generally increasethe force that will overcome the compressed force 267 of bias springs231,232 and increase the axial displacement between the poppet valve 205and valve seat 204. A lower intensity level may generally decrease theforce opposing compressed force 267 of bias springs 231,232. The energystored in bias springs 231,232, may cause bearing 229 to bear againstcam portion 245 and force cam portion 245, cam gear 238, pinion gear 242and shaft 241 to a position that may reduce the axial displacementbetween the poppet valve 205 and valve seat 204. If the valve is open,and the electrical control signal to the D.C. motor 237 is interrupted,the compressed force 267 of bias springs 231,232, may generally causebearing 229 to bear against cam portion 245 and force cam portion 245,cam-gear 238, pinion gear 242 and shaft 241 to a position that will seatpoppet valve 205 on valve seat 204 and essentially block fluid flowbetween inlet 202 and outlet 203.

Referring to FIGS. 7, 11, 12, 13 and 14, valve assembly 200 has a leadframe 246 imbedded in cover 247. The cover 247 may be attached tohousing 201 by crimp ring 268, threaded fasteners, or other suitablemeans. A seal 251 may be located between the cover and housing toprevent debris from entering the housing. FIG. 14 shows the lead frame246 with cover material removed and FIG. 13 shows cover material overmolded on the lead frame 246. The lead frame 246 may include severalindividual terminals, for example terminals 259 and 248 may provideelectrical connection to D.C. motor 237 and a position sensor 249. Amolded electrical connector 250 is formed in cover 247. A matingconnector, with terminals, may engage electrical connector 250 and theterminals of lead frame 246 and make the electrical connections to anelectrical control unit (ECU) 252.

The valve position and fluid flow may be controlled by a closed loopcontrol system that may be part of an ECU 252 shown in FIG. 7. The ECU252 may provide a control signal to the D.C. motor 237 and receive apoppet valve position feedback signal from position sensor 249. Positionfeedback signal is typically a position sensor output voltage. Eachvalve position will correspond to a specific position sensor outputvoltage. The ECU 252 may adjust the control signal to the D.C. motor toachieve and maintain a specific valve position that corresponds to thespecific valve position sensor output voltage. For some conditions ismay be desirable not to have bearing 229 bear against cam portion 245.For example, to ensure poppet valve 205 is completely seated on valveseat 204, it may be desirable to apply an electrical control signal tothe D.C. motor that will cause D.C. motor 237, cam-gear 238, and camportion 245 to rotate to a position that prevents cam portion 245 fromcontacting bearing 229. This may ensure poppet valve 205 is completelyseated on valve seat 204. During this condition, there will be no forceapplied to the cam-gear 238 or cam portion 245 and it may move or causeunwanted noise during conditions such as high vibration. It may bedesirable to apply an electrical control signal to the D.C. motor 237that will cause the cam-gear 238 to rotate to a position where aphysical stop 260, formed in cam-gear 238, engages a physical stop inthe cover 247, housing 201, or other suitable valve assembly component.The intensity level of the electrical control signal can be adjustedbased upon factors such as the level of vibration or other factors. Thiselectrical control signal may be referred to as a “holding” signal.

The position sensor 249 may be a non-contacting type and may usemagneto-resistive, inductive or Hall Effect technology. Sensor 249 mayhave a sensing circuit 253 that will receive feedback from a sensingelement 254.

FIG. 15 shows one variation of an enlarged section of cover 247 withposition sensor 249. Sensing circuit 253 may be attached to the cover247 by snap retention features 261, heat staking, metal clips,overmolding or other suitable means. Sensor circuit leads 262 may beconnected to the terminals 248 of lead frame 246 by welding, soldering,contact pressure, or other suitable means. It should be noted positioncircuit 253 is an integrated circuit that does not require a printedcircuit boards, resistor, capacitors or other components.

The sensing element 254 may be attached to the stem link 228, valve stem206, or other suitable location. For example, the sensing element 254 invalve assembly 200 may be a permanent magnet that may be over moldedinto link 228. Sensing element 254 must be spaced within a specificlocation of sensing circuit 253. Cover 247 has first a first surface269, that will locate and limit sensing element 254 in a firstdirection, and a second surface 270 that will locate and limit sensingelement 254 in a second direction. Sensing element 254 may provide asensing parameter that will be measured by sensing circuit 253. Thesensing circuit may measure the variable parameter, such as a variablemagnetic field or magnetic field direction, when valve stem 206 ismoved, in directions A and B, in response to an electrical controlsignal applied to D.C. motor 237. The sensing circuit will provided avalve position voltage that corresponds to a specific valve position.

It may be noted this sensing arrangement will provide actual valveposition since the sensor element 254 is attached to link 228 and it ismoving with valve stem 206 and poppet valve 205. This would beconsidered an advantage over the position sensing arrangement used forvalve assembly 100 where the position sensor measures the position ofthe output shaft and an implied valve position is determined.

A number of variations may be directed to the physical relationship ofthe cam portion 245, bearing 229, and valve stem 206. Referring to FIG.12, the center of bearing 229 may be aligned with the longitudinalcentral axis 255 of valve stem 206. The central axis 256 of cam portion245 may have been offset 258 from the longitudinal central axis 255 byan amount that will cause the force, transmitted by the cam portion 245to bearing 229, to be applied essentially along the longitudinal centralaxis 255 of valve stem 206. The point of contact between the cam portion245 and bearing 229 is shown as point 257 in FIG. 12. This point isessentially on the longitudinal central axis 255 of valve stem 206.Applying the force directly along the longitudinal central axis 255 ofvalve stem 206 may minimize radial forces on the valve stem that maycause friction and reduce the axial force applied to valve stem 206. Theoffset may be 0.5 mm to 2.0 mm or another value dependent in part by thesize and shape of the cam portion 245.

What is claimed:
 1. A product comprising: at least one housing, a valvestem having a longitudinal axis and supported in the housing forproviding for axial movement, a cam-gear supported in the housing andhaving a central axis of rotation, and including a cam portionintegrated therewith and formed about the central axis of rotation, thecam-gear having a plurality of teeth; an electric motor having a motorshaft, and a pinion gear having a plurality of gear teeth, the piniongear connected to the motor shaft to be rotated thereby, the pinion gearbeing connected to the cam gear to rotate the cam gear; wherein, whenthe cam-gear and cam portion are rotated, the cam portion operablytransmits a force to the valve stem causing the valve stem to moveaxially and; wherein the central axis of rotation of the cam portion isoffset by a distance from the longitudinal central axis of the valvestem and so that the force transmitted by the cam portion to valve stemis essentially along the longitudinal central axis of the valve stem. 2.The product of claim 1 wherein the offset distance, in part, being afunction of the size and shape of the cam portion.
 3. The product ofclaim 1 further comprising; a link operably connected to the valve stemand moveable with the valve stem, a bearing operably connected to thelink and contacting the cam portion of the cam gear and, wherein, whenthe cam-gear and cam portion are rotated, the cam portion operablytransmits a force to the bearing, the link, and the valve stem causingthe bearing, the link, and valve stem to move axially, wherein the linkis interposed between the bearing and the valve stem.
 4. An actuator andvalve product comprising: at least one housing for containing andsupporting actuator and valve components; the housing including: a firstport for receiving a fluid, a second port for delivering a fluid, avalve seat disposed between the first and second port; a valve membercoaxial with the valve seat for controlling flow through the valve seat;a valve stem having a longitudinal axis and attached to the valvemember; an actuator portion within the housing including a motor with arotatable shaft and pinion gear connected to the rotatable shaft and thepinion gear having a plurality of teeth; a cam-gear rotatable with themotor and pinion gear; the cam-gear having a central axis of rotationand a cam portion integrated therewith and formed about the central axisof rotation, the cam-gear having a plurality of teeth; wherein, when themotor, with the rotatable shaft and pinion gear, rotates the cam-gearand cam portion, the cam portion operably transmits a force to the valvestem, causing the valve stem and valve member to move axially in adirection toward the valve seat; and wherein the central axis ofrotation of the cam portion is offset by a distance from thelongitudinal central axis of the valve stem and the force, operablytransmitted by the cam portion to the valve stem, is essentially alongthe longitudinal central axis of the valve stem.
 5. A productcomprising: at least one housing, a valve stem having a longitudinalaxis and supported in the housing for providing for axial movement, acam portion constructed and arranged in the at least one housing tooperably transmit a force to the valve stem causing the valve stem tomove axially; and wherein a central axis of rotation of the cam portionis offset by a distance from the longitudinal central axis of the valvestem, and so that the force transmitted by the cam portion to valve stemis along a longitudinal central axis of the valve stem, the cam gearhaving a plurality of teeth; an electric motor having a motor shaft, anda pinion gear having a plurality of gear teeth, the pinion gearconnected to the motor shaft to be rotated thereby, the pinion gearbeing connected to the cam gear to rotate the cam gear.
 6. A product asset forth in claim 3 wherein the bearing is a ball bearing.
 7. A productas set forth in claim 6 wherein the ball bearing is connected to thelink by a pin.
 8. A product as set forth in claim 1 wherein the valvestem has a first longitudinal end and wherein the cam portion ispositioned above the first longitudinal end.
 9. A product as set forthin claim 3 further comprising at least one spring having one end bearingagainst the link and the other end bearing against the housing.
 10. Aproduct as set forth in claim 3 further comprising two springs eachhaving one end bearing against the link and the other end bearingagainst the housing.
 11. A product as set forth in claim 1 furthercomprising a valve connected at a first end of the valve stem, andwherein the force transmitted by the cam portion to valve stem is in adownward direction toward the valve.
 12. A product as set forth in claim11 wherein the valve is a poppet valve.
 13. A product as set forth inclaim 4 wherein valve member is connected at a first end of the valvestem, and wherein the force transmitted by the cam portion to valve stemis in a downward direction toward the valve member.